This invention generally relates to load bearing members and more particularly to an improved elongate structural member in the form of a truss, fabricated, at least in part, from strut, the term xe2x80x9cstrutxe2x80x9d being used in the industry as referring to a channel-shaped member of the type shown, for example, in co-assigned U.S. Pat. No. 5,022,614.
Conventionally, prefabricated structural trusses provide a primary mechanism for spanning and supporting distances within building structures. These trusses may be manufactured and assembled as generic parts, off-site. On-site installation is simplified because the installation crew can install a pre-assembled truss, rather than building the truss by hand on-site. The primary function of a structural truss is to provide support for floors, ceilings, and related objects in modern buildings. Trusses are conventionally constructed from pairs of angle bars acting as chords and bar rod formed in a zigzag configuration spanning a distance between the chords and acting as a web (see FIG. 1). The chords and web are typically joined by welding.
Structural trusses are often installed in horizontal series, creating an array of trusses. Truss arrays are then installed as sub-floors in multistory buildings. Decking and finish flooring are conveniently placed on top of a truss array, forming a floor. The bottom of the truss array may then be used to attach various intermediate attachment items, such as strut, for supporting objects beneath. These objects, supported from the items, include electrical wires, electrical fixtures, telephone and computer related cables, plumbing hardware, climate control equipment, ventilation ducts, etc. Direct attachment of these objects to the truss array is not possible, because trusses do not offer attachment features. Suspending the aforementioned objects from conventional truss arrays is typically accomplished by attaching strut members to a truss array. Strut members are elongate channel-shaped members which are typically roll-formed from elongate metal sheets of uniform thickness. The channel of the strut allows for attachment of items to the strut, and objects may then attach to those items. For illustration of the prior art means for attachment, reference can be made to co-assigned U.S. Pat. No. 4,037,098 (swivel connector), U.S. Pat. No. 4,146,074 (fastener), U.S. Pat. No. 4,238,157 (connector), U.S. Pat. No. 4,305,557 (pipe hanger), U.S. Pat. No. 4,460,299 (fastener), U.S. Pat. No. 5,022,614 (one-piece conduit clip), U.S. Pat. No. 5,100,086 (cable tray support system), U.S. Pat. No. 5,163,644 (conduit clamp), U.S. Pat. No. 5,209,619 (channel nut fastener), and U.S. Pat. No. 5,848,770 (clevis hanger)
Among the several objects and features of the present invention may be noted the provision of an elongate structural member which permits ready attachment of objects directly to the member; the provision of an elongate structural member which efficiently incorporates the load bearing qualities of a truss and the attachment benefits of strut; the provision of an elongate structural member which permits attachment of objects from below, beside, and above the member; the provision of an elongate structural member which incorporates channel shaped struts as part or all of one or more chords of the member; the provision of an elongate structural member which permits the chords to function as electrical wiring raceways; the provision of an elongate structural member which permits ready attachment of cross bracing between two or more structural members for increased lateral rigidity; the provision of selecting and varying the type of trusses installed for a particular application, increasing the flexibility of the design and allowing building designers to choose load bearing members while considering what objects need be attached below and above the truss; the provision of efficiently incorporating the benefits of strut into a commercially successful truss design; and the provision of an elongate structural member fabricated at least in part from strut and adapted for applications where the chords of the member are not parallel.
Generally, an elongate structural member comprises a first chord, a second chord and a web. The first chord and second chord extend lengthwise of the structural member with a space therebetween. The web spans the space and is comprised of at least one length of metal bar stock of solid cross section. The web further has bends along the length of zigzag configuration. A first set of bends is disposed along a first margin of the web and a second set of bends is disposed along a second margin of the web. The first chord comprises at least two struts, one on each side of the web at a respective margin of the web. Each strut is comprised of a metal channel having generally opposing side walls constituting flanges. The flanges have inwardly directed lips at their outer ends which are spaced from one another to define a slot therebetween. The slot extends the length of the strut. Each strut is secured in engagement with the respective side of the web and is adapted for insertion through its slot of items to be retained in the strut.
In a second embodiment of the present invention, an elongate structural member comprises a first chord, a second chord and a web generally as set forth above. The web structure is comprised of at least a plurality of metal bars extending diagonally with respect to the chords. One set of bars on one side of the chords have end portions in engagement with the outside of the strut and another set of bars on the other side of the chords have end portions in engagement with the outside of the strut. The end portions of the bars are secured to the strut.
In a third embodiment of the present invention, an elongate structural member comprises a first chord, a second chord and a web generally as set forth above. The first chord is comprised of at least two struts with flanges and inwardly directed lips. Each of the lips has a hook-like configuration for gripping engagement by the items to be retained in the strut.
In a fourth embodiment of the present invention, an elongate structural member comprises a first chord, a second chord and a web generally as set forth above. The first chord is comprised of at least two struts with flanges and inwardly directed lips. The lips extend inwardly from the respective flanges toward one another a distance of at least xe2x85x9 inch.
In a fifth embodiment of the present invention, an elongate structural member comprises a first chord, a second chord and a web generally as set forth above. The web is constructed of structural members other than metal channel.
Other objects and features will be in part apparent and in part pointed out hereinafter.